I build everything on my desktop. It's a 4.3Ghz i7 4770K with 32Gb of ram running windows 7.For rendering I went with pixelplow though. I remember rendertimes between 3.5 and 5h a frame. I try not to go over 6h as it becomes tough to manage above that. This times were with terragen 3, when rendering the first shot with terragen 4 it went down to 2.5 hours a frame...I rendered with a AA of 16 at the end and even with that I still had noise and some fireflies but I dealt with that in Nuke.

For the last shot though I couldn't get a clean render without ridiculous rendertimes so I ended up doing a lowres version of the forest and bring it in Nuke to project two 4k frames on it. This worked surprisingly well!

I'm sorry if I misunderstand what you meant, but are you saying that it took 3.5 or 4 hours each frame?? BTW I also understand that you use AA of 16? If so, let me tell you: that, is an extremely high setup and render time. rarely I use AA 8 or higher. if you have noisy renders, there is something in the scene that cause it. maybe you forgot, or you ignore it, but there is many ways to optimize any scene in TG: for example check the atmos quality, if you are using fog, check there is an excessive setting or unnecessary like "recive shadows from surface" enable or "cloud quality" in 0.2, for example. GI settings can also very problematic. I dont know, just to keep it in mind for your next animation, assuming I understood correctly what you meant